Although I can easily write XSL stylesheets that import other XSL
stylesheets and use them with a simple C# .Net XSL testing Gui, it
appears that they didn't make the transformation engine in BTS2004
support <xsl:include> nor <xsl:import> statements. I try and I get
"Resolving of external URIs was prohibited". I found this error being
had by .Net developers, SQL Server developers, and BizTalk developers
alike. I think it must have something to do with which exact transform
override they used behind the scenes.

So it looks like copy-paste re-use may be what we're limited to. I
have thought of other (more strange) ideas like having a helper dll
that is called by the custom XSLT which would load the XSL (from an
embedded resource file or off of network share) to acheive the desired
XSL reuse, but that feels like I'm getting a bit too far outside the
box.

cliff - made it clear that this is a deciding factor on whether they
will buy BizTalk Server - got no answers that I can see, but the thread
got closed.
http://groups.google.com/group/microsoft.public.biztalk.general/browse_thread/thread/c7cd671ef4dd45cd/f7d68e27b344a080?lnk=st&q=%22Resolving+of+external+URIs+was+prohibited%22&rnum=3&hl=en#f7d68e27b344a080